Study of CO2/CH4 Solubility in Liquid Octane

Carbon dioxide (CO2) separation from natural gas is a crucial process in purifying the gas stream to meet customer’s requirement. With the present technology of physical solvents requires higher energy to be operated mostly at low temperature, the operation is quite costly and expensive. Development of solvent has been considered in improving gas absorption economically such that having a higher CO2 loading at higher temperature decreasing the energy requirement for refrigeration purposes & reduces cost. As CO2 content in natural gas is increasing nowadays, a hydrocarbon solvent which is liquid alkane specifically octane (C8H18) is used as an alternative in providing more capacity in absorption purposes. Hence, this research project will study more on the solubility of CO2/CH4 in octane in determining its feasibility in the industry, in terms of different pressure and temperature conditions. The scope of study of this work includes creating a simulation of the solubility test using Aspen HYSYS software to obtain theoretical results. Experiments of gas solubility test using equilibrium cell were also conducted within the time frame of this project. The solubility of CO2/CH4 was determined based on two main parameters which are pressure and temperature. HYSYS simulation has been done simulating the equilibrium cell with the results being obtained at a range of pressure from 30 up to 50 bar. Experiments were done at pressure 30 bar with different temperatures of 308.15K, 318.15K and 328.15K for both CO2 and CH4 gases respectively. In accordance with the principle theory of absorption of gases, it is found that the solubility of CO2 and CH4 components increases with the increasing in pressure with the decreasing in temperature for both experimentally and through simulation.